Messages in this thread | | | Subject | Re: `quirk_usb_handoff_xhci` takes 60 ms with ASM1042 | From | Paul Menzel <> | Date | Wed, 5 May 2021 10:27:52 +0200 |
| |
Dear Greg,
Thank you for the quick reply.
Am 05.05.21 um 10:11 schrieb Greg Kroah-Hartman: > On Wed, May 05, 2021 at 09:57:44AM +0200, Paul Menzel wrote:
>> On an Asus F2A85-M PRO, BIOS 6601 11/25/2014, with an ASM1042 SuperSpeed USB >> Host Controller [1b21:1042], and the xHCI drivers built as modules >> >> CONFIG_USB_XHCI_PCI=m >> CONFIG_USB_XHCI_HCD=m >> >> `quirk_usb_handoff_xhci` takes 60 ms, which is 15 % of the time to reaching >> `run_init_process()`. I addded some prints, showing the f >> >> [ 0.308841] pci 0000:03:00.0: PCI->APIC IRQ transform: INT A -> IRQ 17 >> [ 0.369858] pci 0000:03:00.0: handshake done with timeout = 0 >> [ 0.369862] pci 0000:03:00.0: hc_init reached >> [ 0.369865] pci 0000:03:00.0: second handshake done >> [ 0.369869] pci 0000:03:00.0: third handshake done >> [ 0.369909] pci 0000:03:00.0: quirk_usb_early_handoff+0x0/0x670 took 59661 usecs >> […] >> [ 0.415223] Run /lib/systemd/systemd as init process >> >> Is there a way to optimize this, or move it out “the hot path”? > > That's the hardware taking so long, all that function does is make some > PCI calls to the device.
In your experience, do most devices take that long?
> If the driver is built as a module, there should not be any "hot > path" here as the module is loaded async when the device is > discovered, right? obj-$(CONFIG_USB_PCI) += pci-quirks.o
So all quirks are run independently of the USB “variant” (UHCI, OHCI, EHCI, xHCI).
Indeed, this driver is built into the Linux kernel.
$ grep USB_PCI .config CONFIG_USB_PCI=y
So, should `pci-quirks.c` be split up to have more fine grained control?
> What is waiting for this module to load in order to cause your init to > stall? Perhaps fix your initramfs logic or build the driver into the > kernel itself to take it off of this "load all the modules and wait" > path?
Sorry, for causing some confusion. But as written above, this all happens before the initrd is involved.
Kind regards,
Paul
| |